1. Field of the Invention
The present invention relates in general to an internal combustion engine. In particular, the present invention relates to a control mechanism of the engine for controlling the throttle and choke valves of at least one charge former of the engine.
2. Description of Related Art
To start a cold engine, the fuel/air ratio of a fuel charge delivered to the engine should contain a higher concentration of fuel (i.e., be "richer") than under when the engine is running under normal conditions. Conventional carburetors use various types of cold starting devices to produce a richer charge when starting a cold engine. For instance, a choke valve is used in a conventional carburetor to decrease air flow into a mixture chamber of the carburetor, and consequently the concentration of fuel in the charge is increased. With the closure of the choke valve, a corresponding throttle valve of the carburetor also should be at least partially opened to start the engine.
Throttle and choke valves, however, commonly are operated independently of each other, and starting the engine typically involves a complicated procedure. The user initially pulls a choke knob to close the choke valve and partially opens the throttle valve by rotating the hand grip of a conventional throttle control mechanism. The user then pulls a starter rope to start the engine. Once started, the user opens the choke valve by pushing the choke knob back to its initial position.
Users of outboard engines, however, tend to forget to either close the choke valve or open the throttle valve when starting the cold engine. A cold engine generally will not start without performing both steps. Users, thus, often become frustrated when trying to start the engine when they have forgotten to open the throttle or close the choke.